Lithium compounds such as lithium cobaltate (LiCoO2) and lithium nickelate (LiNiO2) are widely used is cathode material for both lithium secondary cells and thin film micro-batteries due to its high reversibility to lithium ions, high cell capacity and less fading capacity over LiMn2O4.
In general, lithium cobaltate materials are prepared by solid state thermal method and soft chemistry (like sol-gel) methods. The common materials for the preparation of this cathode lithium cobaltate (LiCoO2) are any one of the lithium salts viz. lithium nitrate or is lithium hydroxide, lithium acetate lithium carbonate with cobalt nitrate or cobalt oxide. Soft chemistry methods are mainly used to prepare the intercalation compounds at low temperatures and to reduce the particle size of the compounds. But the soft chemistry routes are multi-step procedures, prolonged time for calcination and expensive. Prolonged heating time, mechanic grinding and intermittent cooling are major drawbacks of solid state thermal procedures. Other preparation methods are also available in literature for preparation of lithium cobaltate like pulsed laser deposition, sputtering and electrostatic spray deposition. Lithium nickelate is also useful as a cathode in lithium secondary cells of high voltage to replace present low energy density secondary storage cells. In the art it is known to prepare lithium nickelate by reacting lithium nitrate, or lithium hydroxides or any other lithium salts with lithium nitrates, acetates, hydroxides or sulphates by a sol-gel process at a temperature in the range of 350-500° C. However, separation of the final product requires several steps.
In the preparation of intercalation compounds, any one of the following disadvantages are observed in the above conventional procedures.    1. Side reactions occur i.e., unexpected product.    2. Unreacted material is left behind which acts as impurity.    3. Partial reactions occur.    4. Several steps are needed for preparation.    5. Controlled conditions required.    6. Long calcination time    7. Nonhomogeneous reactant distribution during heating i.e., undesirable phases are formed.Reference:    1. “Synthesis and electrochemical properties of LiCoO2 spinel cathodes”—S. Chol and A. Manthiram, Journal of the Electrochemical Society, Vol. 149(2) (2002) A162-166.    2. “Fabrication of LiCoO2 thin films by sol-gel method and characterization as positive electrodes for Li/LiCoO2 cells”—M. N. Kim, H. Chung, Y. Park, J. Kim, J. Son, K. Park and H. Kim, Journal of Power Sources, Vol. 99(2001) 34-40.    3. “High temperature combustion synthesis and electrochemical characterization of LiNiO2, LiCoO2 and LiMn2O4 for lithium ion secondary batteries”—M. M. Rao, C. Liebenow, M. Jayalakshmi, M. Wulff, U. Guth and F. Scholz, Journal of Solid State Electrochemistry, Vol. 5, Issue 5(2001) 348-354.    4. “Lithiated cobaltates for lithium—ion batteries—Structure, morphology and electrochemistry of oxides grown by solid state reaction, wet chemistry and film deposition” C. Julien and S. Gastro-Garcia, Journal of Power Sources, Vol. 97-98 (2001) 290-293.    5. “Electrochemical characterization of layered LiCoO2 films prepared by electrostatic deposition”, Won-Sub Yoon, Sung-Ho Ban, Kyung-Keun Lee, Kwang-Bum Kim, Min Dyu Kim and Jay Min Lee, Journal of Power Sources, Vol. 97-98 (2001) 282-286.    6. “Emulsion-derived lithium manganese oxide powder for positive electrodes in lithium ion batteries” Chung-Hsin Lu and Shang-Wei Lin, Journal of Power Sources, Vol. 93 (2001) 14-19.    7. “Cobalt doped chromium oxides as cathode materials for secondary batteries for secondary lithium batteries” Dong Zhang, Branko N. Popov, Yury M. Poddrabansky, Pankaj Arora and Ralph E. White, Journal of Power Sources, Vol. 83 (1999)121-127.    8. “Synthesis and electrochemical studies of spinel phase LiMn2O4 cathode materials prepared by the Pechini process”—W. Liu, G. C. Farrington, F. Chaput and B. Dunn, Journal of the Electrochemical Society., Vol. 143, No.3(1996) 879-884.    9. “Synthesis of electrochemical characterisation of LiMO2 (M=Ni, Ni0.75Co0.25) for rechargeable lithium ion batteries”, Chun-Chieh Chang, N. Scarr and P. N Kumta, J. of Solid State Ionics, Vol 112, 329-344 (1998).    10. “Structural and electrochemical properties of LiNi0.3Co0.7O2 synthesized by different low temperature techniques”, C. Julien, S. S. Michael and S. Ziolkewicz, International Journal of Materials, Vol. 1(1999), 29-37    11. “Synthesis and characterisation of LiCoNi(t-y)VO4 lithium insertion materials”, S. Panero, P. Reale, F. Bonno, B. Serosati, M. Arrabito, D. Mazza and N. Pennazi, J. of Solid State Ionics”, Vol. 128, 43-52, (2000)    12. “Preparation and characterisation of high density spherical LiNi0.8CoO2 cathode material for lithium secondary batteries”, Jierond Ying, Chunrong Wan, Changyin Jiang and Yangxing Li, J. of Power Sources” Vol 99, (2001), 78-84    13. “High temperature combustion synthesis and electrochemical characterisation of LiNiO2, LiCoO2 and LiMn2O4 for lithium ion secondary batteries”, M. M. Rao, C. Liebnow, M. Jayalakshmi, M. Wulff, U. Guth and F. Scholz, J. of Solid State Electrochemistry”, Vol 5, Issue 5, 348-354 (2001)